Generally, foodstuffs such as vegetables and fishes are easily oxidized and rotten by contacting with harmful substances such as microorganisms or oxygen contained in air when the foodstuffs contact with the air.
In addition, microorganisms are reproduced more actively in fermented foods. Therefore, fermentation speed or aging speed of foods is excessively fast such that keeping quality may be deteriorated. Meanwhile, it is very important to block the foods from the outside air so as to delay fermentation and rot of the foods. In order to solve such problems, a sealed container such as a vacuum container is proposed.
As time goes by, the outside air flows and vacuum maintaining force of the currently used vacuum container may be deteriorated. Therefore, foodstuffs or contents that are stored in the vacuum container may be exposed to the air.